RT Journal Article
SR Electronic
T1 Semen quality of fertile Japanese men: a cross-sectional population-based study of 792 men
JF BMJ Open
JO BMJ Open
FD British Medical Journal Publishing Group
SP e002223
DO 10.1136/bmjopen-2012-002223
VO 3
IS 1
A1 Iwamoto, Teruaki
A1 Nozawa, Shiari
A1 Yoshiike, Miki
A1 Namiki, Mikio
A1 Koh, Eitetsu
A1 Kanaya, Jiro
A1 Okuyama, Akihiko
A1 Matsumiya, Kiyomi
A1 Tsujimura, Akira
A1 Komatsu, Kiyoshi
A1 Tsukamoto, Taiji
A1 Itoh, Naoki
A1 Mieno, Makiko Naka
A1 Vierula, Matti
A1 Toppari, Jorma
A1 Skakkebæk, Niels E
A1 Jørgensen, Niels
YR 2013
UL http://bmjopen.bmj.com/content/3/1/e002223.abstract
AB Objectives To establish a base line for future studies on temporal trends, to describe potential geographical differences in semen quality and reference values for studies of men from the general population. Design Cross-sectional study of fertile men from four areas in Japan. Inclusion criteria were: age 20–45 years at the time of invitation, and both the man and his mother had to be born in Japan. Additionally, the current pregnancy of the female partner had to be achieved by normal sexual relations without any fertility treatment. Setting Four Japanese study centres at urban areas located in Sapporo, Osaka, Kanazawa and Fukuoka. Participants 792 men, median age 31.4 years, included from 1999 to 2002. Outcome measures Semen volume, sperm concentration, total sperm count, sperm motility and sperm morphology. Results Semen volumes, percentages of motile spermatozoa and morphologically normal spermatozoa differed slightly between the four groups, whereas no differences in sperm concentrations or total sperm counts were found. In total, 1.2% of men had a sperm concentration below 5 million/ml, 2.1% below 10 million/ml, 3.5% below 15 million/ml and 16.3% below 40 million/ml. For morphology, 14.7% had less than 5% normal spermatozoa. Reproductive hormone levels varied significantly, however, only little from a biological point of view. Conclusions This is the first cross-sectional study on semen quality covering fertile men from the major regions of Japan. It showed that semen quality of fertile Japanese men is comparable to that of the best in European regions. The results may serve as reference values for studies of men from the general population.